The present invention relates to a positive displacement flow meter with helical toothed rotors in which a pair of rotors are rotatable with no pulsation, thereby a tooth-to-tooth surface contact pressure being intended to become zero because of non-existence of energy transmission between the two rotors.
Conventionally, there is known a flow meter with a pair of Roots-type rotors as a positive displacement rotor. A pair of Roots-type rotors are engaged with each other by means of pilot gears directly connected with respective axes of the Roots-type rotors. And it is widely known the disadvantage that an equal rotation of the Roots-type rotors brings about a certain pulsation. The present invention aims to overcome the above disadvantage of the conventional art.